<Background Art 1>
In conventional mobile communication systems, communication services have been provided by wireless base station devices (hereinafter also referred to as macro base stations) each forming a cell having a radius ranging from several hundreds of meters to several tens of kilometers, i.e., an area in which wireless terminal devices are allowed to communicate with the wireless base station device.
In recent years, with a dramatic increase in the number of subscribers of mobile communication services and an increase in communication traffic due to data communication, it is desired to distribute the subscribers and the communication traffic over cells of smaller radii, and to reliably provide the users with a certain level of communication speed. Further, as a countermeasure against dead zones caused by skyscrapers, it is desired to install wireless base station devices in office floors and ordinary households.
In association with these requirements, downsizing of wireless base station devices has progressed due to remarkable improvement in throughput of various devices used in the wireless base station devices, and downsized base stations have attracted attention.
Such small-size base stations (hereinafter also referred to as “femto base stations”) form femto cells. Since the radius of each femto cell is as small as about 10 meters, it is considered that the femto base stations are used in places, such as homes and underground malls, which are outside macro cells foamed by macro base stations and where it is difficult to install macro base stations.
Further, since a large number of femto base stations are installed in a specific area, it is difficult to connect the femto base stations directly to a core network. Therefore, it is considered that a large number of femto base stations installed in a specific area are connected to a gateway device such as a HeNB-GW, and then the femto base stations are connected to the core network via the HeNB-GW.
In the above configuration, when installing femto base stations, if configuration of each femto base station is performed by a telecommunication carrier or a purchaser of the femto base station, considerable labor and cost are required. Further, every time a new femto base station is installed and thereby the number of femto base stations increases, not only configuration of the newly installed femto base station but also reconfiguration of already-installed neighboring femto base stations need to be performed.
In order to solve the above problems, for example, Patent Literature 1 disclosed technique as follows. That is, a new cell measures signal intensities of different channels used by already-existing cells. Then, the new cell forms a list of candidate channels corresponding to channels having relatively high signal intensities, and transmits this list to a mobile switching center of a cellular network. The mobile switching center determines which candidate channels correspond to beacons used in the existing cells, and transmits, to the new cell, configuration information relating to the existing cells. Then, the new cell automatically receives the configuration information relating to the neighboring cells. If the mobile switching center determines that none of the identified neighbors (neighboring cells) reaches a maximum value N, the mobile switching center requests the new cell to transmit an additional candidate channel (i.e., a candidate channel having a lower signal intensity).
<Background Art 2>
In conventional mobile communication systems, communication services have been provided by wireless base station devices (hereinafter also referred to as macro base stations) each forming a cell having a radius ranging from several hundreds of meters to several tens of kilometers, i.e., an area in which wireless terminal devices are allowed to communicate with the wireless base station device.
In recent years, with a dramatic increase in the number of subscribers of mobile communication services and an increase in communication traffic due to data communication, it is desired to distribute the subscribers and the communication traffic over cells of smaller radii, and to reliably provide the users with a certain level of communication speed. Further, as a countermeasure against dead zones caused by skyscrapers, it is desired to install wireless base station devices in office floors and ordinary households.
In association with these requirements, downsizing of wireless base station devices has progressed due to remarkable improvement in throughput of various devices used in the wireless base station devices, and downsized base stations have attracted attention.
Such small base stations (hereinafter also referred to as “femto base stations”) form femto cells. Since the radius of each femto cell is as small as about 10 meters, it is considered that the femto base stations are used in places, such as homes and underground malls, which are outside macro cells formed by macro base stations and where it is difficult to install macro base stations.
Further, since a large number of femto base stations are installed in a specific area, it is difficult to connect the femto base stations directly to a core network. Therefore, it is considered that a large number of femto base stations installed in a specific area are connected to a gateway device such as a HeNB-GW, and then the femto base stations are connected to the core network via the HeNB-GW.
In the above configuration, when installing femto base stations, if configuration of each femto base station is performed by a telecommunication carrier or a purchaser of the femto base station, considerable labor and cost are required. Further, every time a new femto base station is installed and thereby the number of femto base stations increases, not only configuration of the newly installed femto base station but also reconfiguration of already-installed neighboring femto base stations need to be performed.
In order to solve the above problems, for example, Patent Literature 1 discloses a technique as follows. That is, a new cell measures signal intensities of different channels used by already-existing cells. Then, the new cell forms a list of candidate channels corresponding to channels having relatively high signal intensities, and transmits this list to a mobile switching center of a cellular network. The mobile switching center determines which candidate channels correspond to beacons used in the existing cells, and transmits, to the new cell, configuration information relating to the existing cells. Then, the new cell automatically receives the configuration information relating to the neighboring cells. If the mobile switching center determines that none of the identified neighbors (neighboring cells) reaches a maximum value N, the mobile switching center requests the new cell to transmit an additional candidate channel (i.e., a candidate channel having a lower signal intensity).
<Background Art 3>
In conventional mobile communication systems, communication services have been provided by wireless base station devices (hereinafter also referred to as macro base stations) each forming a cell having a radius ranging from several hundreds of meters to several tens of kilometers, i.e., an area in which wireless terminal devices are allowed to communicate with the wireless base station device.
In recent years, with a dramatic increase in the number of subscribers of mobile communication services and an increase in communication traffic due to data communication, it is desired to distribute the subscribers and the communication traffic over cells of smaller radii, and to reliably provide the users with a certain level of communication speed. Further, as a countermeasure against dead zones caused by skyscrapers, it is desired to install wireless base station devices in office floors and ordinary households.
In association with these requirements, downsizing of wireless base station devices has progressed due to remarkable improvement in throughput of various devices used in the wireless base station devices, and downsized base stations have attracted attention.
Such small base stations (hereinafter also referred to as “femto base stations”) form femto cells. Since the radius of each femto cell is as small as about 10 meters, it is considered that the femto base stations are used in places, such as homes and underground malls, which are outside macro cells formed by macro base stations and where it is difficult to install macro base stations.
Further, since a large number of femto base stations are installed in a specific area, it is difficult to connect the femto base stations directly to a core network. Therefore, it is considered that a large number of femto base stations installed in a specific area are connected to a gateway device such as a HeNB-GW, and then the femto base stations are connected to the core network via the HeNB-GW.
In the above configuration, when installing femto base stations, if configuration of each femto base station is performed by a telecommunication carrier or a purchaser of the femto base station, considerable labor and cost are required. Further, every time a new femto base station is installed and thereby the number of femto base stations increases, not only configuration of the newly installed femto base station but also reconfiguration of already-installed neighboring femto base stations need to be performed.
In order to solve the above problems, for example, Patent Literature 1 discloses a technique as follows. That is, a new cell measures signal intensities of different channels used by already-existing cells. Then, the new cell forms a list of candidate channels corresponding to channels having relatively high signal intensities, and transmits this list to a mobile switching center of a cellular network. The mobile switching center determines which candidate channels correspond to beacons used in the existing cells, and transmits, to the new cell, configuration information relating to the existing cells. Then, the new cell automatically receives the configuration information relating to the neighboring cells. If the mobile switching center determines that none of the identified neighbors (neighboring cells) reaches a maximum value N, the mobile switching center requests the new cell to transmit an additional candidate channel (i.e., a candidate channel having a lower signal intensity).
<Background Art 4>
In conventional mobile communication systems, communication services have been provided by wireless base station devices (hereinafter also referred to as macro base stations) each forming a cell having a radius ranging from several hundreds of meters to several tens of kilometers, i.e., an area in which wireless terminal devices are allowed to communicate with the wireless base station device.
In recent years, with a dramatic increase in the number of subscribers of mobile communication services and an increase in communication traffic due to data communication, it is desired to distribute the subscribers and the communication traffic over cells of smaller radii, and to reliably provide the users with a certain level of communication speed. Further, as a countermeasure against dead zones caused by skyscrapers, it is desired to install wireless base station devices in office floors and ordinary households.
In association with these requirements, downsizing of wireless base station devices has progressed due to remarkable improvement in throughput of various devices used in the wireless base station devices, and downsized base stations have attracted attention.
Such small base stations (hereinafter also referred to as “femto base stations”) form femto cells. Since the radius of each femto cell is as small as about 10 meters, it is considered that the femto base stations are used in places, such as homes and underground malls, which are outside macro cells formed by macro base stations and where it is difficult to install macro base stations.
Further, since a large number of femto base stations are installed in a specific area, it is difficult to connect the femto base stations directly to a core network. Therefore, it is considered that a large number of femto base stations installed in a specific area are connected to a gateway device such as a HeNB-GW, and then the femto base stations are connected to the core network via the HeNB-GW.
In the above configuration, when installing femto base stations, if configuration of each femto base station is performed by a telecommunication carrier or a purchaser of the femto base station, considerable labor and cost are required. Further, every time a new femto base station is installed and thereby the number of femto base stations increases, not only configuration of the newly installed femto base station but also reconfiguration of already-installed neighboring femto base stations need to be performed.
In order to solve the above problems, for example, Patent Literature 1 discloses a technique as follows. That is, a new cell measures signal intensities of different channels used by already-existing cells. Then, the new cell forms a list of candidate channels corresponding to channels having relatively high signal intensities, and transmits this list to a mobile switching center of a cellular network. The mobile switching center determines which candidate channels correspond to beacons used in the existing cells, and transmits, to the new cell, configuration information relating to the existing cells. Then, the new cell automatically receives the configuration information relating to the neighboring cells. If the mobile switching center determines that none of the identified neighbors (neighboring cells) reaches a maximum value N, the mobile switching center requests the new cell to transmit an additional candidate channel (i.e., a candidate channel having a lower signal intensity).
<Background Art 5>
In conventional mobile communication systems, communication services have been provided by wireless base station devices (hereinafter also referred to as macro base stations) each forming a cell having a radius ranging from several hundreds of meters to several tens of kilometers, i.e., an area in which wireless terminal devices are allowed to communicate with the wireless base station device.
In recent years, with a dramatic increase in the number of subscribers of mobile communication services and an increase in communication traffic due to data communication, it is desired to distribute the subscribers and the communication traffic over cells of smaller radii, and to reliably provide the users with a certain level of communication speed. Further, as a countermeasure against dead zones caused by skyscrapers, it is desired to install wireless base station devices in office floors and ordinary households.
In association with these requirements, downsizing of wireless base station devices has progressed due to remarkable improvement in throughput of various devices used in the wireless base station devices, and downsized base stations have attracted attention.
Such small base stations (hereinafter also referred to as “femto base stations”) form femto cells. Since the radius of each femto cell is as small as about 10 meters, it is considered that the femto base stations are used in places, such as homes and underground malls, which are outside macro cells formed by macro base stations and where it is difficult to install macro base stations.
Further, since a large number of femto base stations are installed in a specific area, it is difficult to connect the femto base stations directly to a core network. Therefore, it is considered that a large number of femto base stations installed in a specific area are connected to a gateway device such as a HeNB-GW, and then the femto base stations are connected to the core network via the HeNB-GW.
In the above configuration, when installing femto base stations, if configuration of each femto base station is performed by a telecommunication carrier or a purchaser of the femto base station, considerable labor and cost are required. Further, every time a new femto base station is installed and thereby the number of femto base stations increases, not only configuration of the newly installed femto base station but also reconfiguration of already-installed neighboring femto base stations need to be performed.
In order to solve the above problems, for example, Patent Literature 1 discloses a technique as follows. That is, a new cell measures signal intensities of different channels used by already-existing cells. Then, the new cell forms a list of candidate channels corresponding to channels having relatively high signal intensities, and transmits this list to a mobile switching center of a cellular network. The mobile switching center determines which candidate channels correspond to beacons used in the existing cells, and transmits, to the new cell, configuration information relating to the existing cells. Then, the new cell automatically receives the configuration information relating to the neighboring cells. If the mobile switching center determines that none of the identified neighbors (neighboring cells) reaches a maximum value N, the mobile switching center requests the new cell to transmit an additional candidate channel (i.e., a candidate channel having a lower signal intensity).